Method of fabricating aluminum hinge leaves



March 18, 1969 G. a. MORTON 3,432,899

METHOD OF FABRIC/WING ALUMINUM HINGE LEAVES Filed Aug. 14. 19s? Sheet Of 2 A/A/ 5. M0670 INVENTOR L f 32- 3 gzid MW Arrow/5r March 18, 1969 a. B. MORTON METHOD OF FABRICATING ALUMINUM HINGE LEAVES Filed Aug. 14, 1967 Sheet mun 64 /VA/ 5. Mae/UN INVENTOR awaze;

ATTOZA/fy United States Patent 11 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a method of fabricating aluminum hinge leaves each of which has a series of spaced tongues of enlarged cross section extending laterally from one longitudinal side of the leaf, the object of the invention being to reduce cost and also to prevent a strip of extruded aluminum hinge stock from bowing when it is notched to form hinge tongues. A long strip of aluminum is extruded of the cross sectional configuration of two hinges positioned edge to edge, the two opposite longitudinal side edges of the strip being enlarged in thickness to provide material for the hinge tongues. The long strip is split longitudinally into two pieces by means of a series of pairs of rotary blades which are adjusted for successively deeper penetration and which not only split the long strip but also pinch the edges of the resulting two split strips. The pinching action along a severed edge tends to lengthen the edge and thus serves to prevent bowing of a severed strip when the opposite enlarged edge is subsequently notched.

BACKGROUND OF THE INVENTION The hinge leaves which are produced by the invention are relatively thin members used for hingedly mounting small panels, doors, and the like, especially on airplanes. The thickness of the aluminum, for example, may range from .050" to .070". One longitudinal edge of such a leaf has spaced tongues which are enlarged in thickness and which are bored to receive a hinge pin.

For the purpose of fabricating such hinges, aluminum strips are commonly extruded in approximately forty foot lengths, each strip being thickened along one of its longitudinal edges to provide material for the hinge tongues. The extruded aluminum strips are then hardened by heat treatment. The heat treatment consists of dipping the aluminum bars endwise into a molten salt bath and then quickly quenching the aluminum. The heat treatment causes internal stresses because the whole length of the extruded aluminum strip cannot be heated at once and cannot be quenched at once and, therefore, a subsequent stretching operation is employed to straighten out the heat-treated aluminum strip.

To produce the desired hinge leaves, the heat-treated extruded aluminum strip is notched along its thickened longitudinal edge to form hinge tongues but the notching operation causes the notched edge to expand longitudinally with consequent bowing of the aluminum strip laterally. A common practice to straighten out such a bowed notched strip is to run the opposite thinner plain edge of the strip through a pair of pinch rolls which spread the metal and thereby tend to increase the longitudinal dimension of the second edge.

The invention teaches that the cost of fabricating such aluminum hinge leaves may be substantially reduced, first, by reducing the cost of extruding the hinge stock and, second, by eliminating the necessity of employing pinch rolls in a separate operation to straighten a bowed strip.

The manner in which the invention reduces the cost of the extruded aluminum may be understood when it is considered that conventional extruded hinge stock weighs less than V pound per foot and an aluminum mill loses money on extruding aluminum stock that weighs less than pound per linear foot. The reason is that a high scrap loss is involved in the extrusion of such a slender strip and the high scrap loss makes it necessary to extrude twice as much strip as is sold.

For example, the base price for extrusions weighing more than pound per foot may be $1.00 per pound with a price diflerential for ordering less than a given minimum number of pounds. The price dilTerential for an order of less than the minimum pounds may be $.50 per pound and an added price differential for ordering aluminum strips that weigh less than A pound per foot may be $1.50 per pound to make a total cost of $3.00 per pound for the extruded hinge stock.

The invention avoids both the $.50 differential and the $1.50 dilferential to reduce the cost of the aluminum hinge stock by two-thirds. The invention further teaches how an extruded aluminum strip of hinge stock may be produced without any inherent tendency whatsoever for the stock to bow laterally in response to the notching operation.

SUMMARY OF THE INVENTION The invention teaches a method of producing aluminum hinge leaves which is characterized by the concept of extruding hinge stock of double width to raise the weight of the extruded strip to more than V pound per foot and thereby avoid the price differential that is incurred when the extrusions weigh less than A pound per foot. The double width extrusions are purchased in suflicient quantities to avoid the further penalty of $.50 per pound for small orders.

The double width aluminum hinge stock has a cross sectional configuration of two hinge leaves positioned edge to edge with their thinner edges in abutment. Thus, the double width hinge stock has both of its opposite longitudinal edges enlarged in thickness to provide material for the hinge tongues. The double width hinge stock is then split longitudinally to provide two single width strips of binge stock of conventional'cross sectional configuration.

If such a double width strip of hinge stock is split longitudinally by a simple shearing operation or by a sawing operation, the subsequent operation of notching the enlarged edges of the two single width strips would result in bowing of the strips in the manner heretofore discussed. It has been discovered, however, that if a double width extruded strip of hinge stock is split longitudinally by a series of spaced progressive metal penetrating means, the result is complete elimination of any tendency for a severed strip to warp or bow in response to a subsequent notching operation. In the preferred practice of the invention the series of metal penetrating means comprises a series of pairs of symmetrically beveled rotary blades which engage the double width aluminum strip along opposite faces thereof and penetrate the metal progressively with a pinching action. Thus, the invention teaches how a double aluminum strip of hinge stock may be split and pinched simultaneously.

The features and advantages of the invention may be understood from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which are to be regarded as merely illustrative:

FIG. 1 is a plan view of a typical aluminum hinge as produced by the invention;

FIG. 2 is a transverse cross section of a double width extruded aluminum strip of hinge stock;

FIG. 3 is a plan view of the same strip;

FIG. 4 shows the result of splitting the double width hinge stock and then notching the thickened edge of one of the narrower strips;

FIG. 5 is a fragmentary enlarged view showing how a pair of rotary blades as seen along the line 55 of FIG. 7 may cooperate to penetrate the metal of the double strip for the purpose of splitting the double width strip longitudinally;

FIG. 6 is a simplified plan view of the presently pre ferred embodiment of an apparatus for carrying out the step of splitting a double width strip longitudinally;

FIG. 7 is a simplified side elevation of the same embodiment of the apparatus;

FIG. 8 is a simplified fragmentary end elevation of the same apparatus;

FIG. 9 is a diagram of a control system that may be employed for the apparatus; and

FIG. 10 is an enlarged broken transverse sectional view of a newly severed half of a double width aluminum strip.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a typical aluminum hinge comprising two leaves 10 each of which has a plain longitudinal edge 12 and a series of spaced tongues 14 along its opposite edge. The tongues 14 are of enlarged or thickened cross section and are bored in a well known manner to receive a hinge pin 16.

FIGS. 2 and 3 show an extruded aluminum strip generally designated 18 of double width hinge stock which has the cross sectional configuration of a pair of hinge leaves with their plain edges in abutment. Thus, the double width strip is formed with beads or enlargements 20 along its opposite longitudinal edges to provide material for the previously mentioned hinge tongues 14.

The double width extruded strip 18 is split longitudinally in the manner indicated in FIG. 5 to produce two single width strips 22 each of which has a bead or enlargement 20 along one of its longitudinal edges. Each of the two single width strips 22 is then notched at spaced points along its thickened edge to produce a notched strip 24 shown in FIG. 4. The notched strip 24 is then cut into short lengths to produce the individual hinge leaves 12 and then the tongues 14 of each leaf are bored to receive a hinge pin.

In the preferred practice of the invention the operation of splitting a double width strip 18 longitudinally is carried out by a plurality of pairs of rotary blades which engage the strip along its opposite faces and are adjusted to penetrate the strip by stages until the strip is completely split. FIG. 5 shows a pair of the rotary blades 25 that nearly complete the longitudinal splitting of the double width aluminum strip. The two rotary blades 25 are double beveled, i.e., beveled, on opposite sides of their cutting edges 26 and the cutting edges are aligned in a common plane.

If the thickness of the central portion of the double width extruded strip 18 is nominally .050" the series of pairs of rotary blades may be adjusted for progressive penetration of the metal of increments of approximately .010". If the nominal thickness of the stock is .070" the pairs of rotary blades will be adjusted to penetrate the metal by slightly greater increments. The pairs of blades may be adjusted to require less than all six pairs for complete severance of the metal strip but is to be borne in mind that the process of extruding a metal strip gives the metal a decided longitudinal grain and if an attempt is made to sever the metal completely by a single pair of rotary blades, the result will be splitting of the metal in advance of the rotary blades.

The construction of the preferred embodiment of apparatus to carry out the method of the invention may be understood by reference to FIGS. 5-8.

FIG. 5 shows how a double width aluminum strip 18 may slidingly rest on a horizontal support or guide 28 with one longitudinal edge of the double Width strip in sliding abutment against a longitudinal guide 30. FIG. 5 further shows that the upper rotary blade 25 may be an idler blade mounted on a stub shaft 32 that is journalled in a bearing 34, the bearing being fixedly mounted on a longitudinal frame member 35. The lower rotary blade 25 is a driven blade mounted on a shaft 36 that is journalled in a corresponding bearing 38 on the frame member 35. The shaft 36 is actuated by means of a sprocket 40 that is mounted on the outer end of the shaft.

In the drive arrangement shown in FIG. 7, the upper rotary blades of three of the five pairs of successive rotary blades are driven by sprockets 40 and the lower rotary blades of the remaining two pairs are driven by other sprockets 40. A suitable motor 42 mounted at a low level on the frame structure of the apparatus actuates a drive sprocket 44 by means of reduction gearing and a single sprocket chain 45 loops around the various sprockets 44 in a serpentine manner shown in FIG. 7.

A double width aluminum strip 18 is fed to the apparatus from the right end of the apparatus as the apparatus is viewed in FIGS. 6 and 7 and suitable means is provided to press the double width strip downwardly against the previously mentioned horizontal support 28 and to press the double width strip laterally against the previously mentioned horizontal guide 30.

The means to press the double width aluminum strip downwardly against the horizontal support 28 may comprise two spaced rollers 46 shown in FIG. 7. Each of the rollers 46 is mounted by means of a clevis 48 on a piston rod 50 which extends downwardly from a power cylinder 52. The upper ends of the power cylinders 52 are rigidly mounted on brackets 54 which in turn are mounted on the frame member 35. Each of the two rollers 46 is maintained in longitudinal alignment with the apparatus by means of a corresponding yoke 56 which is fixedly mounted on the corresponding clevis 48, the yoke having two guide pins 58 which slide in corresponding apertures in guide ears 60 that are fixedly mounted on opposite sides of the corresponding power cylinder. Preferably, the two power cylinders 52 are actuated by compressed air to extend the two rollers 46 as required, concealed springs retracting the rollers when the two power cylinders are not energized.

Suitable means for maintaining the double width aluminum strip 18 in sliding contact with the longitudinal guide 30 may comprise a roller 62 that is positioned to abut a longitudinal edge of the double width strip. As best shown in FIG. 9, the roller 62 may be mounted by an arm 64 on an angular lever 65 that is mounted by a pivot 66 on a fixed bracket 68. The outer end of the angular lever 65 is connected by a link 70 to a piston rod 72 that extends from a fixed power cylinder 74. Concealed springs in the power cylinder 74 advance the piston rod 72 when the power cylinder is not energized. The power cylinder 74 is preferably operated by compressed air and when energized retracts the piston rod 72 to swing the arm 64 clockwise into pressure engagement with the side edge of the double width aluminum strip.

In the preferred mode of operation of the apparatus, the two rollers 46 and the third roller 62 are normally retracted to permit a double width strip to be introduced endwise into the apparatus. The aluminum strip may be first positioned more or less at random on the apparatus at approximately the desired longitudinal alignment with the apparatus and then the power cylinders 52 and 74 may be energized to force the double width aluminum strip against the horizontal support 28 and against the longitudinal guide 30. The operator may then advance the double width strip endwise towards the series of pairs of rotary blades 25 after first energizing the motor 42 to actuate the rotary blades. The rotary blades then pull the double width strip longitudinally through the apparatus and simultaneously split the double width strip into two single width strips.

The preferred embodiment of the apparatus is provided with a suitable control system which includes a master control in the form of an air valve 75 controlled by a handle 76 which is conveniently positioned for operation by the knee of the operator. As shown in FIGS. 6 and 9, the control system further includes a small power cylinder 77 provided with a plunger 78 which is positioned to 0p erate a microswitch 80 that controls the circuit for the motor 42.

As shown diagrammatically in FIG. 9, the air valve 75 supplies compressed air from a suitable source to a manifold 82 that is connected b two branches 84 to the two power cylinders 52 and is connected by a third branch 85 to the power cylinder 74. A fourth branch 86 is connected to the power cylinder 77 by means of an orifice fitting 88 that causes delay in the operation of the power cylinder 77 relative to the operation of the power cylinders 52 and 74.

The manner in which the apparatus functions for its purpose may be understood from the foregoing description. When the operator feeds the leading end of a double width aluminum strip 18 to the apparatus, the control handle 76 is operated by knee pressure with the immediate consequence that the two rollers 46 press the double width aluminum strip downwardly against the horizontal support 28 and the guide roller 62 presses the double width aluminum strip laterally against the longitudinal guide 30. With a short time delay to permit completion of the alignment of the double width aluminum strip, the microswitch 80 is operated by the plunger 78 to energize the motor 42. The operator then pushes the double width aluminum strip lengthwise into engagement with the first pair of rotary blades 25 whereupon the rotary blades engage the double width strip and pull the double width strip through the apparatus until the double width strip is completely servered. The pairs of rotary blades penetrate the metal of the double width strip incrementally to successive depths and the penetration of the metal by stages results in a definite pinching action by the bevels of the rotary blades so that the double width metal strip is not only split in two pieces but also and simultaneously the severed edges of the two pieces are spread longitudinally by pinching action. The pinching action, in effect, prestresses the plain edges of the single width strips 22 so that when a single width strip 22 is subsequently notched to form a notched strip 24 shown in FIG. 4, the notched strip remains straight after the notching operation instead of bowing laterally in response to the notching operation.

FIG. shows the cross sectional configuration of a single strip 22 at it leaves the apparatus. It is important to note that the longitudinal edges 90 at the opposite faces of the strip along the severed edge of the strip are smooth burr-free edges. There is a tendency for a longitudinal burr to be formed intermediate the two faces as indicated at 92, but this burr is easily removed by light contact against an abrasive wheel to result in a smoothly finished edge. The final steps are to notch the single width strip 22 to produce the notched strip 24 and then to cut the notched strip 24 into individual hinge leaves, the tongues 14 of the hinge leaves being then bored to receive hinge pins.

My description in specific detail of the presently preferred practice of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

1. A method of fabricating aluminum hinge leaves each of which has a series of spaced tongues of enlarged cross section extending laterally from one longitudinal side of the leaf, characterized by the steps of:

extruding a long aluminum strip at least twice as wide as a hinge leaf with the opposite longitudinal side edges of the strip enlarged in cross section in accordance with the enlarged cross section of the tongues of a hinge leaf; and

severing the double width aluminum strip along a longitudinal line to split the double width strip into two single width strips each having one plain side edge and an opposite longitudinal edge of enlarged cross section;

subsequently notching the enlarged longitudinal side portions of each of the severed strips; and

severing individual hinge leaves from each notched single width strip.

2. A method as set forth in claim 1 which includes the step of:

squeezing the metal of the strip across its thickness adjacent opposite sides of the longitudinal line simultaneously with the severing operation to create longitudinal stresses in the plain longitudinal side edges of the two severed strips,

whereby the created longitudinal stresses in the plain edges of the two severed strips compensate for the tendency of the enlarged side edge of each of the two severed strips to elongate with consequent lateral bowing of the severed strip in response to a subsequent notching operation for forming tongues in the severed strip along the enlarged edge of the severed strip.

3. A method as set forth in claim 2 in which the opera. tion of splitting the double width strip is carried out by the steps of:

arranging a series of spaced metal penetrating means aligned longitudinally of the double width aluminum strip; and

causing relative movement between the series of penetrating means and the strip longitudinally of the strip to cause the penetrating means to traverse the length of the strip with each succeeding penetrating means adjusted to penetrate deeper into the metal than the preceding penetrating means to cause complete severance of the metal strip whereby the successive penetrating means progressively squeeze the metal of the strip across its thickness.

4. A method as set forth in claim 3 in which each of said penetrating means comprises a pair of symmetrically beveled rotary blades aligned with each other on opposite sides of the double width strip,

the spacing between the rotary blades of the pairs of rotary blades being reduced in the succeeding pairs for penetration of the metal by stages and simultaneous squeezing of the metal.

5. A method as set forth in claim 4 which includes the steps of:

initially aligning the double width strip longitudinally with the series of pairs of rotary blades;

moving the double width strip endwise into engagement with the rotary blades; and

actuating the rotary blades to cause the rotary blades to move the strip longitudinally for carrying out the splitting operation.

6. A method as set forth in claim 4 in which the double bevel of the rotary cutting blades produce a longitudinal burr along the severed edge of each of the two single width severed strips intermediate the planes of the two opposite faces of the strip; and

which includes the further step of removing said burr from each of the severed strips.

7. In an apparatus of the character described for severing a metal strip longitudinally and for simultaneously squeezing the metal across the thickness of the strip to produce two severed metal strips each with one squeezed longitudinal edge, the combination of:

-a series of pairs of double beveled rotary blades to traverse the metal str-ip longitudinally to split the strip,

said rotary blades being aligned longitudinally of the strip with the two rotary blades of each pair positioned to engage opposite faces of the strip,

the spacing between the blades of each successive pair of blades being reduced relative to the spacing of the preceding pair to cause the pairs of rotary blades to cooperate for progressive squeezing of the metal of the strip and progressive penetration of the metal of the strip for the complete splitting of the strip; and

means to maintain the strip in longitudinal alignment with the rotary blades.

8. Apparatus as set forth in claim 7 which includes means to provide power to move the strip longitudinally relative to the series of rotary blades.

9. Apparatus as set forth in claim 7 which includes:

a support for sliding contact with the underside of the strip;

a longitudinal guide for sliding contact with one longitudinal side edge of the strip; and

retractible means to urge the strip against said support and against said longitudinal guide member.

10. An apparatus as set forth in claim 9 which includes control means to operate said urging means and to start said power means in sequence.

11. Apparatus as set forth in claim 10 in which said power means is a motor with a normally open circuit and which includes first pneumatic means to operate said urging means, second pneumatic means to close said circuit; and

which includes means to supply compressed air to said first and second pneumatic means in sequence.

References Cited UNITED STATES PATENTS 1,906,648 5/1933 Soss 29-11 RICHARD H. EANES, JR., Primary Examiner. 

